The Upper Lip Bite Test

Objective: We conducted a prospective, double-blind study todetermine whether a difficult endotracheal intubation could be predicted preoperatively by a simple new technique, theupper lip bite test and compared it with three other tests used for prediction of difficult intubation: Modified Mallampaticriteria (MMC), Thyromental distance (TM) and Mouth opening (MO). Materials and Methods: Five hundred patients,aged above 16 years, and presenting for elective surgery were subjected to the following assessments: (1) Upper lipbite test (ULBT), class I: lower incisors can bite the upper lip above the vermilion line; class II: lower incisors can bitethe upper lip below the vermilion line; class III: lower incisors cannot bite the upper lip; (2) Oropharyngeal classaccording to the MMC. (3) The distance between the chin and thyroid cartilage (thyromental distance). (4) Extend ofmaximum mouth opening test. Results: ULBT had significantly higher accuracy (96%) and specificity (98.3%) and thelowest rate of false positive (p< 0.001). The most sensitive test was the TM test (42%). Conclusion: We concludedthat comparison of the three tests, UPBT has sufficient value in predicting difficult intubation in adults